Disrupted sleep could contribute to a higher risk of death, a study suggests.

Research examined the impact of “unconscious wakefulness” on a person’s risk of dying from heart disease or any cause.

Academics said “arousal burden” is associated with long-term cardiovascular and all-cause mortality in women and to a lesser extent in men

The phenomenon is a normal part of sleep, but when it accounts for a larger proportion of sleep it can become a problem, the authors suggested.

Common triggers can be obstructive sleep apnoea or noise.

The study, published in the European Heart Journal, saw researchers examine sleep data from more than 8,000 men and women.

The participants, aged 64 to 83, were followed up for between six and 11 years.

During the follow-up period, the researchers noted that people with higher rates of arousal burden had a higher risk of death.

Women with an arousal burden of 6.5% or more of their night’s sleep had a 12.8% increased risk of death from cardiovascular disease.

Typically, people will feel exhausted and tired in the morning because of their sleep fragmentation but will not be aware of the individual arousals

Overall the risk of dying from any cause was 21% among women of the same age in the general population, which increased to 31.5% among women with an arousal burden of more than 6.5%

The research team, led by associate professor Mathias Baumert, from the University of Adelaide in Australia, and Dominik Linz, associate professor in the cardiology department at Maastricht University Medical Centre in The Netherlands, found there was an increased risk for men but it was to a lesser extent – and not statistically significant in some instances.

Prof Linz said: “A common trigger for nocturnal arousals is obstructive sleep apnoea, when breathing stops and the arousal system ensures the activation of our body to change our sleep position and to reopen the upper airway. Another cause of arousals can be ‘noise pollution’ during the night by, for example, night-time aircraft noise.

“Depending on the strength of the arousal, a person might become consciously aware of the environment, but often that is not the case.

“Typically, people will feel exhausted and tired in the morning because of their sleep fragmentation but will not be aware of the individual arousals.”